轻链近端肾小管病

32岁男性,病程4个月,临床表现为血清肌酐升高伴大量蛋白尿,尿沉渣镜检正常,近端肾小管损伤(低血钾、低血尿酸、低血磷、尿糖阳性),肾脏体积增大,血游离轻链比值异常(κ/λ=76.92),免疫固定电泳见κ型单克隆免疫球蛋白条带,两次骨髓穿刺示浆细胞分别占3%、0.5%,未见原始和幼稚浆细胞,肾活检示肾小管上皮细胞内见结晶形成,肾小管上皮细胞胞质λ轻链阳性,电镜示见肾小管上皮细胞内结晶形成,最终诊断为轻链近端肾小管病。予硼替佐米联合地塞米松治疗4个疗程,血清M蛋白转阴,肾功能改善,尿蛋白减少。

Light chain proximal tubulopathy

32-year-old male with a 4-month course presented with elevated serum creatinine associated with large albuminuria,no microscopic hematuria,proximal tubular injury(hypokalemia,hypouricemia,hypophosphatemia and positive of urine-glucose),and bilateral kidney enlargemrnt was shown by renal ultrasound.Immunofixation electrophoresis indicatied monoclonal κ band and elevated κ free light chain(κ/λ=76.92) was tested..Plasma cells were 3% and 0.5% respectively by bone marrow inspiration twicey,and no primitive and immature plasma cells were observed.Renal biopsy revealed formation of intracellular crystals in tubular epithelial cells.The renal tubular epithelial cells were cytoplasmic kappa light-chain positive.Electron microscopy revealed formation of intracellular crystals in tubular epithelial cells.The final diagnosis was light chain proximal renal tubular diseases.After 4 courses of bortezomib combined with dexamethasone,no M protein can be dectectd,and renal function improved,together with the decreasement of the urinary protein.